[racket] Enhancing a macro

Thanks Jeremiah!

I took your idea and modified it slightly so that the let**-debug is
in the body of the parameterize.  It works great.

Cheers,
Harry

(define indent-size (make-parameter 0))
(define-syntax let**-debug
  (syntax-rules ()
    [(let**-debug tmp a ...) (parameterize ([indent-size (+ (indent-size) 5)])
                               (let**-dbg tmp a ...))]))

(define-syntax let**-dbg
  (syntax-rules ()
    [(_ tmp body)
     (begin (display (make-string (indent-size) #\space))
            (displayln 'body)
            (time (begin0 body (display (make-string (indent-size)
#\space)) )))]
    [(_ tmp a b ... body)
     (let ([tmp (begin (display (make-string (indent-size) #\space))
                       (displayln 'a)
                       (time (begin0  a (display (make-string
(indent-size) #\space)))))])
       (let**-dbg tmp b ... body))]))


On Wed, Aug 22, 2012 at 8:57 PM, Jeremiah Willcock <jewillco at osl.iu.edu> wrote:
> On Wed, 22 Aug 2012, Harry Spier wrote:
>
>> I have a macro let**-debug (based on the let** macro from Matthias
>> Felliesen) which gives me timing information.
>>
>> (define-syntax let**-debug
>>  (syntax-rules ()
>>    [(_ tmp body) (begin (displayln 'body) (time body))]
>>    [(_ tmp a b ... body) (let ([tmp (begin (displayln 'a) (time a))])
>> (let**-debug tmp b ... body))]))
>>
>> It works fine.  The idea is that I tune using the form let**-debug and
>> when I'm happy with the results I change let**-debug to let** which
>> still works the same without printing the timing information.
>
>
> What about using a parameter:
>
> (define timing-indent-level (make-parameter 0))
>
>
> (define-syntax let**-debug
>   (syntax-rules ()
>     [(_ tmp body)
>      (begin (displayln 'body)
>             (time (begin0 (display (make-string (timing-indent-level)
> #\space)) body)))]
>
>     [(_ tmp a b ... body)
>      (let ([tmp (begin (displayln 'a)
>                        (time (begin0
>                                (parameterize ([timing-indent-level (+ 2
> (timing-indent-level))]) a)
>                                (display (make-string (timing-indent-level)
> #\space)))))])
>
>        (let**-debug tmp b ... body))]))
>
> This assumes that the operation that you're timing is cheap compared to
> printing things out and modifying parameters.  If it's not, you may need to
> use time-apply and print out the results yourself.
>
> -- Jeremiah Willcock